Given the inner product ⟨f,g⟩=∫01f(x)g(x)dx\langle f, g \rangle = \int_0^1 f(x)g(x) dx⟨f,g⟩=∫01f(x)g(x)dx on P1P_1P1 (polynomials of degree ≤1\leq 1≤1), find the norm of f(x)=1+xf(x) = 1+xf(x)=1+x.
7/3\sqrt{7/3}7/3
7/37/37/3
5/3\sqrt{5/3}5/3
5/35/35/3